Seems like only a month or two ago that some pundits saw almost no way that Mitt Romney could easily sew up his party's nomination, and they spun out elaborate scenarios of a contested convention. Actually, it was only a month or two ago that some pundits were saying that. But now Romney's nomination is assumed, especially after he won five primaries this week. And that leaves him a full half year to make his case against President Obama.

That's one of the subjects we'll discuss with our political brain trust. NPR national political correspondent Mara Liasson is here. Hi, Mara.

MARA LIASSON, BYLINE: Hi, Steve.

INSKEEP: And our Political Junkie columnist Ken Rudin as well. Ken, good morning.

LIASSON: That's right. For all the suspense, there wasn't much suspense. For all the twists and turns of the primaries and all of the time we spent dissecting Romney's weaknesses that the primaries exposed, he comes out of the primaries pretty strong; neck and neck in the polls with this president. And we now see the general election campaign pretty well underway.

The president has scheduled his first official campaign rallies for May 5th. He's going to Ohio and Virginia. We see increasingly heated direct exchanges between Romney and the president. The superPACs are advertising seriously. We even saw clashes over an issue that doesn't get a lot of attention in presidential campaigns, foreign policy, yesterday.

It's only April, but it sure feels like October.

INSKEEP: You got that back-and-forth going, as you often do, as you get down the campaign stretch. Now, Newt Gingrich on his way out of the campaign here. But he made one last try, Ken Rudin, in Delaware.

RUDIN: In Delaware, yeah. Basically having lost two out of 43 primaries is like the proverbial tree in the forest...

INSKEEP: Having won two...

RUDIN: Having won two or three, right - Georgia and South Carolina. But it's interesting. He based a lot of his campaign on Delaware. Had he won Delaware, he would've done what?

(SOUNDBITE OF LAUGHTER)

RUDIN: I mean it's hard to make the case. But 27 percent in Delaware, that's enough, and Newt Gingrich will officially bow out next Tuesday, May 1st; probably endorse Romney at the same time.

INSKEEP: As Delaware goes, so goes...

RUDIN: (Unintelligible) Delaware.

INSKEEP: Not all - with all due respect to Delaware, but it's one state and not one of the bigger ones.

Now all the talk, of course, is about a running mate. So isn't going to be?

RUDIN: Well, let's talk about, first of all, what he needs to do. I mean obviously he's not in the same position that John McCain was in four years ago, where he had to come up with a Hail Mary. He was trailing the Democrats and Barack Obama and he came up with this woman, I believe her name was Sarah Palin.

INSKEEP: Heard of her.

RUDIN: We haven't heard of her since. But the point is, is that they felt they needed to make a big, drastic, dramatic change. He may not have to do that this time. He's basically looking to solidify his ticket. He may not have to win a region. We always talk about when John Kennedy picked Lyndon Johnson. That's what you've got to do. You've got to win a region.

But look, you know, they didn't pick Joe Biden to win Delaware. They didn't pick Dick Cheney to win Wyoming. I think Mitt Romney is going to have to pick somebody he's comfortable with and the Republican Party is comfortable with. But ultimately it's not going to make a difference, 'cause ultimately it's going to be about the presidential candidates.

INSKEEP: Mara Liasson, what about Marco Rubio, briefly?

LIASSON: Well, Marco Rubio has been on the short list for some time. He's a rising star in the party. He's a young Hispanic senator from Florida. He had an audition of sorts this week. He campaigned with Romney in Ohio. He gave a foreign policy speech at the Brookings Institution, which actually was surprisingly nonpartisan - didn't have any of the red meat that you'd expect for somebody auditioning for the job of vice president, who usually is the attack dog on the campaign ticket.

But the point about Romney, I think, is that he has a lot of really good choices. There's Marco Rubio on the list, Rob Portman of Ohio, he has Chris Christie from New Jersey, Bob McDonnell from Virginia. And I think that all of these guys offer something to him. Maybe they could bring their state. Maybe they could bring an ethnic group, like Hispanics. Maybe they could help reinforce his brand and his message about the economy and fiscal policy.

I would say the bottom line is just there's two key qualities that a vice president has to have: no skeletons in his closet and being ready to be president at a moment's notice. That's what was lacking in the Sarah Palin pick and I don't think Mitt Romney will make that mistake.

INSKEEP: Do no harm. Let's talk very, very briefly about Congress. Up to a 14 percent approval rating, by the way, Congress. More conservative Democrats, a couple of them in Pennsylvania, lost in primaries. And a couple of more mainstream Republicans, Orrin Hatch and Richard Lugar, face primaries coming up.

RUDIN: Well, let's talk about Congress. First of all, you have these centrist Democrats, Jason Altmire and Tim Holden of Pennsylvania, they both voted against the President Obama's health care bill. They were defeated by liberals and the unions. And it seems like as a Tea Party is moving the conservative party more to the right, the liberal wing of the Democratic Party, what's left of it, is trying to move the Democratic Party farther to the left.

INSKEEP: Mara, you get the last word here.

LIASSON: Well, two senators - Orrin Hatch in Utah, Dick Lugar in Indiana - both have Tea Party challenges. Both have been in the Senate a very, very long time. I think Orrin Hatch is probably more favored. Dick Lugar has the tougher fight. But both of those are examples of how the Tea Party, while it might have weakened in some ways, still has a lot of fight in it in these states.

INSKEEP: Mara Liasson, thanks very much.

LIASSON: Thank you.

INSKEEP: And Ken Rudin, thanks to you.

RUDIN: Thank you, Steve.

INSKEEP: Our political brain trust here, and we'll continue hearing from them throughout this election year. Transcript provided by NPR, Copyright NPR.